Fluid pressure system



June 9, 1942. c. v. BERGLUND I FLUID PRESSURE SYSTEM Filed Oct. 25, 1939 2 sheets sheet 1 1 N V E NTOR.

Y ATTORNEY.

June 9, 1942. c; v. BERGLUND 2,285,557

FLUID PRESSURE SYSTEM Fil'ed Oct. 25, 1959 2 Sheets-Shee t 2' INVEN Q ATTORNEY.

Patented June 9,1942.

' 2,285,557 FLUID PRESSURE SYSTEM Charles V. Berglund, Detroit, Micln, assignor to Hydraulic Brake Company, Detroit, Mich., a corporation of California Application October 25-, 1939, Serial No. 301,285

13 Claims. (01. (so-54.5)

This invention relates to fluid pressure systems. Broadly the invention comprehends a fluid pressure system for a motor vehicle includ means for actuating the clutch and the brakes of the vehicle.

An object of the invention is to provide a fluid pressure system operative to actuate the clutch and brakes of a motor vehicle in sequence, also individually, or concomitantly, as may be elected by the operator.

Another object of the invention is to provide a fluid pressure system for control of a motor vehicle including means for actuating the clutch and brakes of the vehicle successively'by a single actuator.

, Another object of the invention is to provide a fluid pressure system for control of the clutch and brakes of a motor vehicle includingmeans' for actuating the clutch independently of the brakes, means for actuating the clutch and brakes successively by a single actuator, means for actuating the brakes independently of the clutch, means for actuating the clutch and brakes concomitantly, and means for actuating the clutch and brakes successively and augmenting: the actuative force of the brakes.

' Yet another object of the invention is to provide a fluid pressure system including a duplex fluid pressure producing device or master cylinder having interconnected fluid pressure producing means.

A further object of the invention is to provide a fluid pressure producing device or master cylinder including two interconnected. chambers or cylinders having independent discharge ports and means for displacing fluid from one of the cylinders through its discharge ports and also through the associated cylinder and its discharge port.

Yet a further object of the invention is to provide a'duplex fluid pressure producing device or master cylinder and actuators therefor comprising linkage including a toggle and afoot pad supported on the knee of the toggle.

Other objects and advantages of the invention will appear from the following description taken in connection'with the drawings forming a part of this specification, and in which Fig. 1 is a diagrammatical illustration of a fluid pressure brake system embodying the invention;

' Fig. 4 is a sectional view,.substantial1y on line 4-4, Fig. 3;

Fig. 5 is'a fragmentary view of a braking element and an adjusting device therefor; and

Fig. 6 is a sectional view substantially on line 6-6, Fig. 5. I

Referring to the drawings for more specific details of the invention, a fluid pressure producing device or master cylinder adapted to be attached to the frame of a motor vehiclechassis includes a reservoir l8 having a cover plate l2 provided with a filling opening l4 normally closed as by a plug it having openings I8 therethrough for venting thereservoir to the atmosphere and at the base of the reservoir are corresponding cylinders and 22 arranged in parallel relaport '54.

Fig. 2 is a vertical sectional view of the fluid pressure producing device;

Fig. 3' is atop plan view of the fluid pressure producing device; 2

tion to one another.

The cylinders 20 and 22 are open at one end and closed at the other end as by heads Hand 28 having discharge ports 28' and 30 controlled as by two-way valves 32 and 38. The cylinders have ports 35 and 38 providing communications between the cylinders and the reservoir l8, and the cylinder 22 has a conventional-compensating port 40.

Arranged in the wall of the cylinders adjacent the closed ends thereof are ports and 44 connected by a passage 46 controlled by a spring-- pressed valve 48 providing for the. passage-of fluid onli from the cylinder 22 through the port 44,

the passage 48 and the port 82 into the cylinder 20, and a passage 58v connected to the passage 46 between the valve 48 and the port '42 communicates with, a valve chamber 52 having a port 54 opening into the'reservoir, and a springpressed valve 58 in the chamber 52 controls the The valve 58 is normally held open as by a yoke 58 slidably mounted on a stud 68 in the bottom of the reservoir. As shown, the yoke has depending tangs 62 and 64 on its arms extended through the ports 36 and 38 into the cylinders 28 and 22, and arranged centrally of the yoke is an arm 66 adapted to engage the ball valve 56 so as to'hold the valve open.

5 each including a fixed support or backing plate 12, a drum 14 associated with the backing plate, a pair of conventional corresponding interchange able friction elements or shoes 16 pivoted on the backing plate for cooperation with the drum, 8. retractile spring 18 connecting the shoes, and a motor corresponding to the motors mounted on the backing plate and connected to the shoes for actuating the shoes into engagement with the drum against the resistance of the retractile spring 18.

Each of the friction elements or shoes 16 carries an automatic adjuster, indicated generally at 80. As shown, the rim of the shoe has therein a slot 82, and the web of the shoe has therein an arcuate slot 84, a transverse bore 86, and arranged on the web is a guide pin 88. A lever 90 fulcrumed on the shoe has for its fulcrum a lateral sleeve 92 registering with a bore 94 through the lever, and the sleeve is received by the bore 86. A pin 96 on one end of the lever extends through the arcuate slot 84, and loosely sleeved on this pin is a rectangular washer 98. The other end of the lever is bent upon itself as indicated at I00 so as to embrace the web of the shoe andto provide a means adaptable for engagement with a conventional retractile stop I02 mounted on the backing plate 12.

A block I04 has a diagonal slot I06 extended partly through the block and a transverse bore I 08 adjacent one end of the slot. One end of the block has a radius 0 commensurate with the radius of the shoe, and this end of the block is fitted for movement in the slot 82 through the rim of the shoe for engagement with the drum 14.

The diagonal slot I06 in the block receives the rectangular washer 98 on the pin 96 carried by the lever 90, and the bore I08 in the block registers with the lateral sleeve 92 on the lever and the bore 86. A light spring plate II2 flapped against the block over the bore I08 has secured thereto a spring II4 superimposed on the lever 90 serving to frictionally clamp the block and the lever to the web of the shoe.

Because of a differential in the coefficient of friction between the linings of the shoes 16 and the block I04, during a normal braking operation, there is relative movement between the shoe and the block. This movement of the block is proportionate to wear on the lining on the shoe and is transversely of the shoe against frictional resistance imposed by the spring I I4.

During this movement, the rectangular washer 9a in the diagonal slot I06 in the block 104 slides in the slot, and this movement of the washer is transmitted to the lever 90 and imparts thereto slight angular movement of the lever on its fulcrum so that at the conclusion of a braking operation and return of the shoe to its retractile position on the stop I02 the shoe is supported, when the brake is at rest, in proper spaced relation to. the drum.

Because of the wedging action between the guide pin 88 on the web of the shoe and the rectangular washer 9" on the pin 96 carried by the lever, retrograde movement of the block I04 is inhibited. This is of importance becauseof the tendency to maladjustment of the block I04 due to the snapping action of the retractile spring 89 connecting the shoes 16, occurring upon release of the brake at the conclusion of a braking operation.

A fluid pressure delivery pipe or conduit H6 connects the discharge port 30 of the cylinder 22 to a fluid pressure actuated motor H8 suitably connected to and operative for activating an actuator I20 of a conventional clutch, not shown.

Corresponding pistons I22 and I24 reciprocable in the cylinders 20 and 22 are held against displacement by washer I26 seated on retaining rings I28 fitted in grooves in the walls of the cylinders adjacent their open ends. Each of the pistons has ahead I30, a reduced body portion I32 providing in conjunction with the wall of the cylinder an annular chamber I34 communicating with the reservoir I0 by way of the ports 36 01 38, and a skirt I36 supporting a sealing cup I38.

When the pistons are in retracted position, the heads I30 of the pistons normally engage the tangs 62 and 64 on the yoke 58 to retain the arm 66, also on the yoke, in engagement with the ball valve 56 so as to hold the valve open. The head I30 of each piston has a plurality of passages I40 therethrough providing communication between the annular chamber I34 and that portion of the cylinder forward of the piston. A collapsible sealing cup I42 seated on the head of each piston controls the passages I40, and a spring I44 interposed between the sealing cup I42 and the two-way valve 32 or 34 serves to retain the cupand valve against displacement and also to return the piston to retracted position.

The piston I22 has in its back a recess I46 for the reception of one end of a thrust pin I48 havingon its other end a coupling I50 connected to the open end of the cylinder 20 as by a flexible boot I52, for exclusion of dust and other foreign substances from the cylinder. A rod I54 connects the coupling I50 to a lever I56 rockable on stub shafts I58 and connected as by a retractile spring, not shown, to a fixed support,and a toggle I60 connecting the lever I56 to a fixed support I62 preferably arranged on the foot board of the vehicle has pivoted to itsknee a foot pad I64.

correspondingly, the piston I24 has in its back va recess I66 for the reception of one end of a,

thrust pin I68 having on its other end a coupling I10 connected by a flexible boot I12 to the open end of the cylinder 22 for the exclusion of dust and other foreign substances from the cylinder. A rod I14 connects the coupling I10 to a lever I16 rockable on a stub shaft I18 and connected by a retractile spring, not shown, to a fixed support, and a toggle I connecting the lever to a fixed support I82'suitably arranged on the foot board of the vehicle has mounted on its knees a foot pad I84.

Assuming that the systemis installed one imtor vehicle substantially as illustrated and described, and that the system is filled with a suitable fluid, under these conditions, upon depressing the foot pad I84, the toggle I 80 is spread, and force is transmitted therefrom through the lever I16, the rod I14, and the thrust pin I68 to the piston 1I24 resulting in advancing the piston on its compression stroke.

As the piston advances, the sealing cup on the head thereof closes the compensating port 40, and simultaneously therewith the yoke 58 is released, resultingiin releasing the valve 56, and

consequent closing communication between the disengagement of the clutch, the spring-pressed valve 48 cracks, and fluid is displaced from the cylinder 22 through the port 44, the passage 46, and the port 42 into the cylinder 20, thence past the two-way valve 32 through the discharge port- 28 and fluid pressure delivery pipe 68 and its branches into the fluid pressure actuated motors I0, causing energization of these motors with the resultant movement of the braking or friction Upon actuation of the brakes through the op-- eration hereinabove described, should it be found desirable to apply the brakes with additional force, the operator may depress the foot pad I64. I'his' results in spreading the toggle I60 and transmission of force therefrom through the lever I56, the rod I54, and thrust'pin I48, to the piston I22,

resulting in advancing the piston on its compression stroke accompanied by displacement of fluid from the cylinder 20, past the two-way valve 32, thence through the discharge port 28 and fluid pressure delivery pipe 68 and the branches thereof, into the motors I0, causing further energization of the motors with the resultant further movement of the shoes I5 into. the drums I4. It is, of course, to be understood that the latter operation hereinabove .described may be accomplished independently of the operation of the clutch, and while the clutch is still engaged. A braking operation of this character is common practice in instances where it is desired to check the speed of a motor vehicle without disconnecting the power plant or motor thereof.

Upon conclusion of a normal sole operation of the cylinder 22, the foot pad I84 is released and returns to its normal position under the influence of a conventional retractile spring, preferably connected to the lever I16. This results in release of the piston I24 and return of this piston to its retracted position under the influence of the retractile spring I44, and the consequentrelease of pressure on the fluid in the system. When the piston I24 returns to its retracted position, the yoke 58 is actuated to engage and open the valve 56 so as to estabilsh communication between the reservoir I0 and the cylinder 20.

As the piston I24 returns to its retracted position, a partial vacuum is created in the cylinder 22 forward of the piston. This resultsin drawing fluid from the reservoir I0, through the port 38 into the annular chamber I34, thence through the quantity of fluid in excess of that required to fill the cylinder, and under this condition the excess fluid received by the cylinder 22 is returned to the reservoir III by way of the compensating port 40. This concludes the'cycle in the operation of the clutch only. I

In instances where the clutch and brakes have been operated successively, during the period fluid is returning to the cylinder 22 from the motor H8 and fluid pressure delivery pipe IIG, fluid is also returning to the cylinder 20 from the fluid pressure actuated motors III associated with the brakes and the fluid pressure delivery pipe 68 and its branches connecting these motors to the cylinder 20 under the influence of the retractile springs I8, and since the valve 48 is closed and the valve 56 open, any quantity of fluid received by the cylinder 20 in excess of that required to completely flll'the cylinder is returned to the reservoir by way of the port 42, the passages 46 and 50, the valve chamber 52, and the port 54.

In instances where the brakeshave been actuated independently or to augment the actuation of the brakeswhen operated in conjunction with the clutch, upon conclusion of a brakingv operation, the foot pad I64 is released and is returned to its retracted position under the influence of a conventional retractile spring prefer;

" ton I22, and return of the piston to its'retracted adapted to be closed by the actuation of either position under the influenceof the spring I44.

When the piston is in fully retracted position, the head thereof engages the yoke 58 and opens the valve 56 so as to establish communication between the reservoir and the cylinder 20. As the piston returns to retracted position, a partial vacuum is, created in the cylinder 20, resulting in drawing fluid from the reservoir LII], through the port 36, into the annular chamber I34 back of the piston, thence through the passages I40in the head of the piston, past thesealing cup I42, into that-portion of the cylinder forward of the piston, completely filling the cylinder. During this operation, fluid is returning to the cylinder 20 from the fluid pressure actuated motors III and the fluid pressure delivery pipe 68 and branches thereof connecting these motors to the cylinder 20 under the influence of the retractile springs .18. This may result in the cylinder receiving a quantity of fluid in excess of its capacity, and in that event the excessive fluid is returned from the cylinder 20 to the reservoir It by wayof the port 42, the passages 46 and 50, the valve chamber 52, and port 54.

It is to be understood that the valve 56 is piston I22 or I24 and it is thereby necessary that passages I40, past the sealing cup I42, into that portion of the cylinder forward of the piston, completely filling the cylinder.

During, this operation, the fluid in the fluid pressure actuated motor H8 and the fluid pres-.

sure delivery pipe H6 connecting this motor to the cylinder is returning to the cylinder 22 under the influence of the clutch lever I20 actuated by- 'the clutch under normal operating conditions.

This may result in the cylinder 22 receiving a single actuator, that the brakes may be operated independently, and that the clutch and brakes may be operated successively and the brakes further actuated so as to increase the effectiveness thereof, or to compensate for excessive pedal travel as in instances of fade-out due to drum expansion.

An important factor is the operation of the clutch and brake successively by a single actuator particularly in that the clutch may be held disengaged and the brakes held, applied simultaneously by one foot of the operator so that. the operator's other foot may be free for actuation of the accelerator of the motor of the vehicle. This is particularly desirable when the vehicle has been stopped while ascending an incline, giving the vehicle a tendency to roll backward during the interval of releasing the brake and speeding up the motor of the vehicle.

While this invention has been described in connection with certain specific embodiments, the principle involved is susceptible of numerous other application that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is:

l. A duplex master cylinder unit having two cylinders interconnected by a passage provided with pistons movable in the cylinders for creating pressure, a check valve for control of flow of fluid from one cylinder to the other, a reservoir, and mechanism including a ball valve adapted to be actuated by the pistons operative-to provide communication between said reservoir and said passage when both cylinders are relieved of pressure.

2. A duplex master cylinder'unit having two cylinders interconnected by a passage provided with means controlling flow of fluidfrom one a reservoir, a pair of interconnected cylinders cylinder to the other, a piston in each-cylinder, a

reservoir, means for connecting said reservoir and said passage, and means operated by movement of both pistons to retracted position to actuate said connecting means to open communication between said passage and reservoir and operated upon advance of either of said pistons to actuate said connecting means to close said communication.

3. A fluid pressure system comprising a pressure producing device including a pair of cylinders, a piston movable in each of the cylinders, means providing communication between the cylinders, fluid pressure responsive means controlling the communication, a fluid pressure actuated motor connected to each cylinder, said motors activated successively by actuation of one of the pistons, and one of the motors further activated by actuation of the other piston.

4. A fluid pressure system comprising a pressure producing device including a reservoir, a pair of cylinders supplied, therefrom, a communication between the cylinders, pressure responsive means in the communication, a piston movable in each of the cylinders for creation of pressures on the fluid in the system, an individual fluid pressure actuated motor connected to one of the cylinders, a group of fluid pressure actuated motors connected to the other cylinder, said individual motor and group of motors activated successively upon actuation of one of the pistons, and the group of motors further activated upon actuation of the other piston.

5. A fluid pressure producing device comprising a reservoir, a pair of cylinders associated therewith, a passage connecting at least one of the cylinders with the reservoir, means controlling the passage, a second passage connecting the cylinders, valve means controlling the second passage, pistons reciprocable in the cylinders, and individual actuators for the pistons adapted to permitsole, concomitant or successive operation of the pistons.

the valve having parts extended through the supply ports into the cylinder, and pistons reciprocable in the cylinders adapted to engage said parts when in their retracted position.

'7. A fluid pressure producing device comprising a reservoir, a pair of cylinders associated therewith having supply ports communicating with the reservoir, said cylinders closed at one end as by heads having discharge ports and open' at their other ends, valves for control of the dis charge ports, a passage connecting the'cylinders adjacent the discharge ports, means'controlling the fiow of fluid through the passage, a valve chamber communicating with the reservoir and a passage connecting the chamber to one of the cylindersga valve in the chamber for control of the communication, trip mechanism for the valve having parts extended through the supply ports into the cylinders, pistons reciprocable in the cylinders adapted to engage said parts when in retracted position so as to hold the valve open, and means for actuating the pistons.

8. A fluid pressure producing device comprising communicating directly with the reservoir, pistons movable in the cylinders for creating pressure, means for actuating the pistons, a valve con- I trolling the communication between one of the cylinders and the reservoir, means controlling the flow of fluid from one cylinder to the other, said valve operative to close the communication between the one cylinder and reservoir upon advance of either piston.

9. A fluid pressure producing device comprising a reservoir, a pair of cylinders in direct communication with the reservoir, communication between the cylinders, a discharge port for each 0! the cylinders, pistons reciprocable in the cylinders, .means for actuating the pistons, means controlling the communication between one cylinder and the reservoir, and means actuated by advance of either piston for closing off the communication between the one cylinder and the reservoir. I

10. A duplex master cylinder unit having two cylinders interconnected by a passage provided with pistons movable in the cylinders for creating pressure, a valve for control of flow of fluid from one cylinder to the other, a reservoir, a second passage independent of one cylinder and providing a communication between the other cylinder and the reservoir, a valve means in the second passage, andmeans in the cylinders cooperating with the pistons for control of the valve means.

11. A duplex master cylinder unit having two cylinders interconnected by a passage provided with means controlling flow of fluid from one controlling this passage, a yoke mounted in the reservoir normally retaining the passage between the cylinder and reservoir open when the pistons are in their retracted positions, and operative to permit closing of the valve upon advance of either piston.

12. A fluid pressure system comprising a pressure producing device including a pair or cylinders, a communication between the cylinders, a piston reciprocable in each of the cylinders, means controlling the communication, independent I fluid pressure actuated motors connecting each of the cylinders, said means controlling the communication between the cylinders responsive to predetermined fluid pressure to permit operation of the motors by activating one only of the pis- I tons.

on the fluid in the system, a passage providing 13. A fluid pressure system'comprising apressure producing device including a reservoir, a pair of cylinders supplied therefrom, a communication between the cylinders, a piston movable in each of the cylinders for creation 01. pressures communication between-one of the cylinders and the reservoir, pressure responsive means-in the 7 communication between thecylinders, a valve in v the passage, fluid pressure actuatedmotors conand thereafter as the piston is further advanced to increase the pressure on the fluid, the pressure responsive means between the cylinders is actuated to permit passage of fluid with a conseq'uent actuation of the motors connected to the other cylinder.

CHARLES v. BERGLUND. 

